The PROFINET fiber optic cable schematic below shows the general structure of such a cable, which consists of two parallel wires. The wires are ready for direct assembly of connectors. The orange wire has printed directional arrows to facilitate the assignment of wires to the transmit and receive connections.

The table below lists the minimum requirements for a PROFINET fiber physical layer. The requirements for a fiber optic interface are nearly the same as those for a copper interface, but the second physical layer feature requirement varies.

Fiber Optics Types and Parameters

Fiber type selection should be based on the requirements given by the automation project. In general, there are two types of optical fiber cables: Type B and Type C. Type B optical fiber cables are for stationary or flexible use. Type C optical fiber cables are used mainly for special applications e.g. permanent movement or vibration or torsion.

Four different fiber classes can be employed when using optical fibers for PROFINET. Those four classes are Plastic optical fiber (POF), Glass fiber (multi-mode), Glass fiber (single-mode), and Glass fiber with a plastic jacket (hard-coated silica fiber (HCF) or plastic-coated fiber (PCF)). The table below summarizes some fiber class factors: